Get the parameters passed to the function.

If `phalcon_fetch_params` is called before `PHALCON_MM_GROW()` (I prefer this), the first argument should be 0; otherwise 1.
1 instructs to call `PHALCON_MM_RESTORE()` if there is an error parsing parameters.

The second argument is the number of *required* parameters, the third one is the number of *optional* parameters.